Even the most experienced Alfresco developers were new once, and chances are someone has helped you at some point along the way. No matter what your skill level, you can give back by sharing what you know with other users who need support. It's a nice thing to do, and who knows? You might learn something, too!
You can answer questions right here in the Alfresco Community.
You can also hang out with the community on the IRC Chat
The official documentation is at docs.alfresco.com, and you can give us feedback on the official documentation by using the feedback form on each page.
Posting articles related to Alfresco on your personal blog is also very helpful. If you regularly post about Alfresco, let us know.
Finally, improving the pages in this community is a good way to help. Alfresco is a fast moving project, and these community pages do not always keep pace. It takes engaged contributors to keep this community a valuable resource, so please be bold in updating pages! See the community guidelines and the suggestions in Wiki Cleanup. There is also a tag for pages that we know need attention: "Page Needs Work".
Testing Alfresco is a great way to learn about the platform, directly contributes to the stability of the product, helps our engineering team focus on developing cool new features, and is an excellent way for people of all backgrounds to make a valued contribution. Confirming and classifying bugs that are listed in our issue tracker is as important as finding new bugs and providing quality reports. See Reporting an Issue for more details.
Alfresco thrives on developer contributions, in the form of both contributed modules and functionality to core. Helping out in development helps the project move forward and stay competitive, and is the best way to ensure that Alfresco can do what you need it to do on your next project. Most community enhancements start as patches submitted through the issue tracker.